How to Choose an On-Board Charger (OBC) for Commercial EVs
Learn how to choose an on-board charger for commercial EVs: power, voltage, cooling, CAN, IP67, and integration. A practical OBC guide for EV OEM engineers.
Selection Checklist
- ☐ Battery voltage, range, and usable energy are written down.
- ☐ Charging window and AC supply are confirmed with the depot or customer.
- ☐ Required power is calculated with the charging-time formula, with margin for taper.
- ☐ OBC output voltage and current cover the full pack range.
- ☐ Efficiency and power at 110 Vac vs 220 Vac are confirmed.
- ☐ Cooling, mounting, airflow, IP rating, temperature, vibration, and protection are agreed for this vehicle.
- ☐ CAN version, message set, wake-up, and diagnostics are documented.
- ☐ DC-DC power is sized separately, and the 2-in-1 vs separate decision is recorded.
- ☐ Full datasheet, CAN database, and connector details have been requested.
Related reading: 3.3kW vs 6.6kW vs 11kW OBC: Which One Do You Need? · OBC + DC-DC Integration: When Does a 2-in-1 Make Sense? · OBC RFQ Checklist: What EV Manufacturers Should Provide Before Requesting a Quotation
FAQ
What is the difference between an OBC and a DC fast charger?
An OBC is on the vehicle and converts AC to DC. A DC fast charger is off the vehicle and delivers DC directly to the battery. The two solve different problems and are specified differently.
How do I know if I need 3.3 kW or 6.6 kW?
Calculate charging time with the formula above, using usable energy and the real parking window. If 3.3 kW does not fit the window, step up. Do not choose based on cost alone.
Does OBC voltage have to match the battery exactly?
It must cover the battery voltage range, not just the nominal voltage. A 96 V pack may charge up to 115 V, and may discharge to 80 V or lower at the end of its range. Check the output range at temperature extremes and at end of life.
Can I use the same OBC for different vehicle models?
Sometimes, if voltage, power, cooling, mounting, and CAN are the same. In practice, different vehicles usually need different compromises. Check each model against the checklist above.
What should I ask the supplier for before I decide?
Ask for the full datasheet, CAN protocol, connector part numbers, dimensional drawing, weight, cooling requirements, protection functions, and validation evidence: IP, temperature, vibration, salt spray, and EMC.
Related Echelon Products
See the full range on the products page.
Next Step
Send the Echelon engineering team four numbers — battery voltage, pack energy, charging window, and target vehicle — and request a datasheet and RFQ for the matching OBC. That is the fastest way to move from a shortlist to a confirmed selection.
To start, share your vehicle and battery requirements through our contact page, and see how a custom programme is scoped on our OEM/ODM page. Before requesting a quotation, the OBC RFQ checklist lists the inputs that let Echelon quote accurately in one pass.
About Echelon Charger
Echelon Energy Technology specializes in onboard chargers, DC/DC converters, and integrated EV power solutions for commercial and specialty electric vehicles.
For technical discussions, product selection, or OEM/ODM cooperation:
Email: nancy@tici-energy.com
WhatsApp: +86 18114665311
